Impact of specific functional groups in flavonoids on the modulation of platelet activation

Figure 1. Effect of flavones with phenyl B-ring on human platelet activation. (A) Chemical structures of the flavones, F-1, TF-1, CYC-1 and TCYC-1. (B) Representative traces displaying the level of aggregation obtained when human isolated platelets were treated (for 5 minutes) with a vehicle control [0.1% (v/v) DMSO] or various concentrations of flavones, F-1, TF-1, CYC-1 and TCYC-1 (3.125–100 μM) and 0.5 μg/mL CRP-XL. (C) Bar graphs show the percentage of aggregation obtained in the presence and absence of different concentrations of flavones, F-1, TF-1, CYC-1 and TCYC-1. The data were normalised by considering the maximum aggregation observed for the vehicle control at 5 minutes as 100%, and the level of inhibition in flavone and its derivatives-treated platelet samples was calculated accordingly. Cumulative data denote mean ± S.D. (n = 3). The p values displayed (*p < 0.05, ***p < 0.001 and ****p < 0.001) are as analysed by one-way ANOVA using Graphpad Prism.

Figure 2. Effect of flavones with thiofuran B-ring on human platelet activation. (A) Chemical structures of the flavones, F-2, TF-2, CYC-2 and TCYC-2. (B) Representative traces showing the level of aggregation obtained when human isolated platelets were treated (for 5 minutes) with a vehicle control [0.1% (v/v) DMSO] or diverse concentrations of flavones, F-2, TF-2, CYC-2 and TCYC-2 (3.125–100 μM) and 0.5 μg/mL CRP-XL. (C) Bar graphs show the percentage of aggregation obtained in the presence and absence of various concentrations of flavones, F-2, TF-2, CYC-2 and TCYC-2. The data were normalised by considering the maximum aggregation observed for the vehicle control at 5 minutes as 100%, and the level of inhibition in flavone and its derivatives-treated platelet samples was calculated accordingly. Cumulative data denote mean ± S.D. (n = 3). The p values displayed (*p < 0.05, **p < 0.01 and ***p < 0.001) are as analysed by one-way ANOVA using Graphpad Prism.

Figure 3. Effect of flavones with furan B-ring on human platelet activation. (A) Chemical structures of the flavones, F-3, TF-3, CYC-3 and TCYC-3. (B) Representative traces displaying the level of aggregation obtained when human isolated platelets were treated (for 5 minutes) with a vehicle control [0.1% (v/v) DMSO] or various concentrations of flavones, F-3, TF-3, CYC-3 and TCYC-3 (3.125–100 μM) and 0.5 μg/mL CRP-XL. (C) Bar graphs display the percentage of aggregation obtained in the presence and absence of diverse concentrations of flavones, F-3, TF-3, CYC-3 and TCYC-3. The data were normalised by considering the maximum aggregation observed for the vehicle control at 5 minutes as 100%, and the level of inhibition in flavone and its derivatives-treated platelet samples was calculated accordingly. Cumulative data denote mean ± S.D. (n = 3). The p values displayed (*p < 0.05, **p < 0.01, ***p < 0.001 and ****p < 0.001) are as analysed by one-way ANOVA using Graphpad Prism.

Figure 4. Effect of flavones with pyridyl B-ring on human platelet activation. (A) Chemical structures of the flavones, F-4, TF-4, CYC-4 and TCYC-4. (B) Representative traces showing the level of aggregation obtained when human isolated platelets treated (for 5 minutes) with a vehicle control [0.1% (v/v) DMSO] or various concentrations of flavones, F-4, TF-4, CYC-4 and TCYC-4 (3.125–100 μM) and 0.5 μg/mL CRP-XL. (C) Bar graphs show the percentage of aggregation obtained with flavones, F-4, TF-4, CYC-4 and TCYC-4. The data were normalised by considering the maximum aggregation observed for the vehicle control at 5 minutes as 100%, and the level of inhibition in flavone and its derivatives-treated platelet samples was calculated accordingly. Cumulative data denote mean ± S.D. (n = 3).

Figure 5. Cytotoxicity profile of flavones in human platelets. Human isolated platelets were treated with a positive control, or a vehicle control [0.1% (v/v) DMSO] or various concentrations (3.125–100 μM) of flavones, F-1, TF-1, CYC-1 and TCYC-1 (A), F-2, TF-2, CYC-2 and TCYC-2 (B), F-3, TF-3, CYC-3 and TCYC-3 (C) and F-4, TF-4, CYC-4 and TCYC-4 (D) for 30 minutes and the release of LDH, a marker for cytotoxicity was measured at 490 and 650 nm using spectrofluorimeter. The LDH release attained with the positive control was considered as 100%, and the levels of LDH release for flavone-treated samples were calculated. The data represent mean ± S.D. (n = 3). Statistical significance was analysed by one-way ANOVA using Graphpad Prism.